Nanosheets of transition-metal dichalcogenides can be useful, e.g., in electronics, sensing, or catalysis applications. It can be challenging to tune the properties of such nanostructured materials without disrupting their structure too much. Incorporating other atoms, for example, is often limited to isoelectronic replacements. Functionalizations of the surfaces or edges of the nanosheets could provide a useful alternative approach. However, functionalization of the basal plane surface can be difficult because there is a lack of free sites for covalent bonding.

Thomas E. Mallouk, University of Pennsylvania, Philadelphia, USA, The Pennsylvania State University, University Park, USA, and International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, Japan, and colleagues have synthesized basal-plane-functionalized NbS₂ nanosheets.

The team used photolysis to remove a labile carbonyl ligand from a cyclopentadienyl manganese(I) tricarbonyl “piano stool” complex (CpMn(CO)₃). This gave the coordinatively unsaturated fragment CpMn(CO)₂, which is then bonded to electron-rich S atoms on the NbS₂ nanosheet surface. This functionalization was performed using a mixture of NbS₂ and CpMn(CO)₃ in hexanes under a UV lamp and an argon atmosphere.

The product was characterized using infrared (IR) and UV-Vis spectroscopy, as well as X-ray photoelectron spectroscopy (XPS). The results confirmed the Mn–S bonding, and the team found that the coordination of CpMn(CO)₂ to the surface S atoms does not significantly change the oxidation state of the Nb atoms. According to the researchers, the attachment of an organometallic fragment to the basal plane of NbS₂ nanosheets could allow for further functionalizations. This approach could be useful for tuning the properties of transition-metal dichalcogenide nanosheets.

• Basal Plane Functionalization of Niobium Disulfide Nanosheets with Cyclopentadienyl Manganese(I) Dicarbonyl,
  Jarrett D. Dillenburger, Minh An T. Nguyen, Pengtao Xu, Jeffrey R. Shallenberger, Thomas E. Mallouk,
  Inorg. Chem. 2022.
  https://doi.org/10.1021/acs.inorgchem.2c02366